Welcome to the Winobloggers webpage! Students and professors from different universities meet to discuss their findings on Winogradsky columns they constructed!
We learn how to formulate hypotheses, observe, comment, ask and reply to questions related to our scientific experiments.

Winogradksy columns

'In the field of observation, chance only favors the prepared mind' Pasteur 1854

Blog posts

Thursday, 25 May 2017

Final post: ''Results of a Winogradsky column''. Group A4.

In this post we are going to discuss the evolution of the column in the fifth (the last) week,
The surface is more green compairing with the fourth week, due to the growth of microalgae and cianobacteria (aerobic photosinthetic). Furthermore in this part of the column there are more bubbles because there is more oxygen than the previous week.
In the middle of the column the pink is more intense because the anaerobic photosintetic bacteria have been producing more sulphure. For that reason when we hit the column in the table the smell is worse than the last week.
The part of the column that is reached by the sunlight has a brown colour while the otherside is black, due to the presence of heterotrophic bacteria which oxidate iron, in the brown part.
To sum up, comparing with the prediction in the first post we can conclude thet,
1. Halophilic bacteria haven't appeared apparently.
2.Cianobacteria (autotrophic bacteria) have grown in the surface of our column, as we expected.
3.Heterotrophic microorganisms have appeared too (they oxidate iron).
4.Microorganisms which can assimilate the sulfur have appeared.

"2.Cianobacteria (autotrophic bacteria) have grown in the surface of our column, as we expected."Great!

"3.Heterotrophic microorganisms have appeared too (they oxidate iron)."What types of heterotrophic bacteria do you know? Among other hteretrophic groups the ones that use iron are the iron reducers, not iron oxidisers. The latter are usually autotrophs.

"4.Microorganisms which can assimilate the sulfur have appeared."All microorganisms need to assimilate one way or the other S. The pink coloured bacteria are purple sulfur bacteria. They are photosynthetic bacteria that use hydrogen sulfide (H2S) instead of H2O.

I hope the experiment helped you to learn some things on the complexity of microbial metabolisms.